Simple fact is that they have tested the same speakers in mono and stereo configurations on multiple occasions. To quote Toole "without exception" the same speakers were preferred in both scenerios. This is the case regardless of what you are saying the speaker/room position configurations were.
I'm not really interested in arguing with forum members about this. It's a bit tedious TBH. Your opinion simply doesnt carry weight against that of Toole et Al.
Toole himself has written the following:
Therefore, the implication is that spatial factors were strongly influential, if not the deciding factors, in both tests...
Obviously, there is much yet to be investigated, including the tantalizing notion that wide-dispersion loudspeakers with what would appear to be compromised sound quality (AA or E) are given a higher sound quality and spatial quality ratings than a narrow-dispersion loudspeaker with potentially superior sound quality (BB).
The provocative suggestion is that the two domains are interrelated and that the spatial component is greatly influential. Listeners appeared to prefer the sound from wide-dispersion loudspeakers with somewhat colored off-axis behavior to the sound from a narrow-dispersion loudspeaker with less colored off-axis behavior.
Source: Sound Reproduction
@Duke has explained several times that Toole's own data is in one case not consistent (this is not just an opinion, it's in the diagram) and the moment "spatial quality" is rated higher than "sound quality" the order between AA and E is reversed when comparing monophonic to stereophonic.
No more was claimed and certainly no one questioned Tooles paper's general position.
But it applies to this interpretation, of course, that the sample was very small (9 or 10 listener) and that the standard deviation of the ratings is high, compared to the differences in the mean values of loudspeaker AA and E.
Toole did not indicate this in the diagram, so here is the standard deviation for the first evaluations:
There is a difference between critically questioning science (this is how science works) and rejecting it without arguments or simply expressing his own opinion.
But you didn't go into the much more important point at all, namely that the monophonic test setup (if used) is carried out in a way that is meaningful for typical listening rooms - as
described in the Toole paper.
This means that the loudspeaker should not be placed freely in the room (which is often done, e.g. Harman/Olive), otherwise the spatial information and possible radiation problems of the loudspeaker will get lost (or is severely degraded).
During my picture search in the previous post I had overlooked an interesting statement by Sean Olive which supports this very argument. He is quoted as follows:
The experiment takes place in a custom built room with a hidden mechanical speaker shuffler. Recently renovated with a slightly tighter width, Sean says the smaller room size helps increase a greater sense of 1st reflection thus making the test more sensitive to the off-axis performance of the loudspeaker.
Source:
https://audio-head.com/the-harman-tour-part-1-loudspeaker-audio/
To depict a typical listening room, the distance to the side walls is still too far, even in the new listening room, if the listening tests are performed as shown in the picture - IMHO
There was a much more recent test in 2008:
Olive Sean E., Hess Sean, Devantier Allan,
”Comparison of Loudspeaker-Room Equalization
Preferences for Multichannel, Stereo, and Mono
Reproductions:
Are Listeners More Discriminating
in Mono?” presented at the 124th Convention of the
Audio Engineering Society, preprint 7492, (May
2008).
View attachment 79625
Listeners were far more picky about the flaws in the "No EQ" mode when in mono (blue) versus stereo (red) and multi-channel (square). Indeed in Multichannel test listeners barely cared about these large tonality differences.
Also here I am missing some test details. What was the exact test setup?
Some speculations:
Could this have been the test environment?
In a surround setting it is likely that the center speaker was used for the monophonic test and not the left stereo speaker, for example. This would considerably reduce the meaningfulness of the comparison, since the center speaker has no near lateral boundary surfaces.
When listening without EQ, the standard deviation is lowest in the monophonic test, indicating that the listeners were most in agreement there - which argues for speaker tests performed in mono - except, as already mentioned, when the center speaker was used (instead of a stereo speaker).
It seems to me that the room modes have been handled in all EQ methods. That would explain why with EQ the ratings are high. Without EQ, the surround setting gets high ratings because the room modes are also well suppressed there.
Why does the loudspeaker monitored in mono get the highest ratings with EQ?
My assumption would be that the mono speaker was the center speaker and that the tested speaker shows an uneven radiation pattern. Due to the minor lateral reflections, the center speaker could "sound most pleasant" when EQ.
When I've compared (in mono) small domestic loudspeakers in a large auditorium, one surprising finding was that the wider dispersing model still came across as more spacious, despite being 4 to 5 meter away from the nearest wall.
I would agree with that " intuitively". However, it could happen that a loudspeaker with a particularly uneven radiation pattern might sound most interesting because it makes vocals sound particularly close, for example.
In a "normal" listening environment with relatively close lateral boundaries, however, this could then prove to be a negative characteristic.
